Binding Energy Of Shallow Donor Impurity Research Articles

Modeling of the Stark shift and binding energy of shallow donor-impurity in $$\mathrm{GaAs}/{\mathrm{Al}}_{0.3}{\mathrm{Ga}}_{0.7}\mathrm{As}$$ core/shell quantum disk: effects of lateral directed applied electric field including the core/shell sizes

Modeling of the Stark shift and binding energy of shallow donor-impurity in $$\mathrm{GaAs}/{\mathrm{Al}}_{0.3}{\mathrm{Ga}}_{0.7}\mathrm{As}$$ core/shell quantum disk: effects of lateral directed applied electric field including the core/shell sizes

Pressure-related binding energy in (In,Ga)N/GaN double quantum wells under internal composition effects

In the present work, we provide the calculation of the 1s-like binding energy of shallow-donor impurity in symmetric double coupled quantum wells based on non-polar wurtzite (In,Ga)N/GaN. Considering the effective-mass and dielectric mismatches, numerical calculations are performed within the framework of parabolic band and single band effective-mass approximations under the finite potential barrier using finite difference method. The pressure- and Indium-dependent binding energy are principally associated with the effective-mass, dielectric constant, quantum size and potential barrier changes. Our main findings show that the predicted binding energy: (i) is enhanced (dropped) with hydrostatic pressure for large (thin) well, (ii) is declined with wells coupling, (iii) is improved (insensitive) with In-composition for thin (large) well and (iiii) is strongly-modulated by the impurity position.

Hydrogenic impurities in quantum dots under intense high-frequency laser field

The effects of intense high-frequency laser field on photoionization cross-section and binding energy of shallow-donor impurities in GaAs/GaAlAs quantum dots are calculated using variational method with the effective-mass approximation. From these calculations, it has been concluded that the dependences of the impurity binding energy and photoionization cross-section on the intense laser field are very significant.

Effects of an intense, high-frequency laser field on the intersubband transitions and impurity binding energy in semiconductor quantum wells

Within the framework of effective-mass approximation, using a variational method, the effect of high-frequency laser field on intersubband transitions and the binding energy of shallow-donor impurities in a semiconductor quantum well are investigated. We have found that the increase of the laser-dressing parameter leads to important effects on the electronic and optical properties of a quantum well. This gives a new degree of freedom in various device applications based on the intersubband transition of electrons.

Laser-induced reshaping of the density of impurity states in GaAs/AlGaAs nanowires

The binding energy of shallow-donor impurities in a cylindrical quantum well wire irradiated by an intense non-resonant laser field is calculated within the effective mass approximation by using a variational procedure. Accurate laser-dressing effects are considered for both the confinement potential of the wire and the Coulomb potential of the impurity. The computation of the ground state subband energy eigenfunctions for different laser field intensities is based on a bidimensional finite element method. Important changes of the electron probability density under intense laser field conditions are predicted. The study reveals that the laser field compete with the quantum confinement and breaks down the degeneracy of states for donors symmetrically positioned within the nanostructure. A proper analysis of the density of impurity states is found to be essential for controlling the optical emission related to shallow donors in semiconductor quantum wires.

Stress effects on the binding energy of shallow-donor impurities in symmetricalGaAs/AlGaAs double quantum-well wires

The effects of applied compressive stress on the binding energies of shallow-donorimpurity states with a finite confinement potential in symmetrical GaAs/AlGaAsdouble quantum-well wires (DQWWs) are studied theoretically using a variationalprocedure within the effective-mass approximation. Significant results for different wireand barrier widths, shallow-donor impurity positions, and compressive stressalong the growth direction of the structure are obtained taking into account theΓ–X crossover and the image charge effects in the calculations. Our results show that thebinding energy does not change appreciably with the size of the wire and barrier, or withthe donor ion position. We also find that for stress values up to 13.5 kbar, the bindingenergy increases linearly with stress, while for stress values greater than 13.5 kbar, thebinding energies show nonlinear behavior. Moreover, in the limit of double quantumwells (DQWs), our binding energy agrees with previously reported results. It ispointed out that compressive stress is an important factor in studies of the bindingenergies of shallow-donor impurity states in symmetrical GaAs/AlGaAs DQWWs.

The effect of intense laser field on the photoionization cross-section and bindingenergy of shallow donor impurities in graded quantum-well wire under an electricfield

The laser-field dependence of the impurity binding energy and donor-relatedphotoionization cross-section in graded quantum-well wire under an externalstatic electric field is calculated by a variational method and in the effective massapproximation. We have shown that, in the graded quantum-well wire structures,not only the ‘dressed’ potential but also the applied direction of the externalelectric field plays a very important role in the determination of the binding energy.

The effect of an intense laser field on magneto donors in semiconductors

The laser-field dependence of the binding energy of shallow-donor impurities in graded, and square quantum wells under the external magnetic field is calculated by a variational method and in the effective mass approximation. We have shown that, not only the ‘dressed’ potential, but also the shape of the confinement potential, the strength of the external magnetic field parallel to the growth direction, and the impurity position play very important roles in the determining the binding energy of a hydrogenic impurity.

Hydrogenic impurities in graded GaAs–(Ga,Al)As quantum-well wires in an electric field

The electric field dependence of polarizability and binding energy of shallow-donor impurities in graded quantum-well wires is calculated by a variational method and in the effective-mass approximation. We have considered a finite confinement model and the results are compared with that of infinite confinement potential. Our calculations have revealed the dependence of the impurity binding and polarizability on the field direction in the graded quantum-well wire.

Magnetic field dependence of the binding energy of shallow donors in GaAs quantum-well wires

Using a variational procedure within the effective-mass approximation we have calculated the binding energies of shallow-donor impurities in cylindrical GaAs quantum-well wires, in an axial magnetic field and an infinite confinement potential. In contrast to the previous results in quantum wells, we have found that, in the magnetic field, the impurity binding energy may be increased or decreased as a function of the impurity location in the quantum wire. On the basis of analysis of the variation of the binding energy with magnetic field strength, a method is proposed for experimentalists to confirm the presence of a shallow donor in the vicinity of the wire boundary.

Binding energy and polarizability in GaAs–(Ga,Al)As quantum-well wires

By means of a variational scheme and in the effective-mass approximation we have calculated the binding energy of shallow-donor impurities in rectangular-transversal section GaAs–(Ga,Al)As quantum-well wires under an applied electric field. We have considered an infinite confinement model to describe the barriers on the wire boundaries. Depending on the transversal sizes, we can reproduce the results for the infinite quantum wells. We present the results for donor binding energies and polarizabilities of the wires. Our results are in good agreement with previous theoretical findings. This work gives very important information about the binding energy and polarizability that can be taken into account in experimental work related to absorption processes, and carrier dynamics, associated with impurities in these heterostructures.